Paper feeding cassette and image forming apparatus

ABSTRACT

According to one embodiment, a paper feeding cassette includes a sheet storing section, side guides, and a sheet tray. The sheet storing section stores a sheet to be fed. The side guides move in the width direction orthogonal to a sheet feeding direction from the sheet storing section and regulate movement of a sheet end at least to one side in the width direction. The sheet tray lifts a downstream side end in the sheet feeding direction from the inside of the sheet storing section on the lower surface of the sheet stored in the sheet storing section. A through-hole including at least a passing area in the width direction of the side guides is provided in the sheet tray. At least a part of an edge that is present on the downstream side in the sheet feeding direction, faces the through-hole, and extends in the width direction moves closer to the sheet feeding direction as the part of the edge moves further away from the sheet center in the width direction to an end side.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from U.S. provisional application 61/333,183, filed on May 10, 2010; and U.S. provisional application 61/333,181, filed on May 10, 2010; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a technique for stacking sheets using a paper feeding cassette.

BACKGROUND

FIG. 24 is a perspective view of a paper feeding cassette 3A.

The paper feeding cassette 3A in the past of an image forming apparatus includes a cassette case 4 configured to store sheets, side guides 31A and 31B configured to slide in a sheet width direction (a Y direction), and a sheet tray 5A on which the sheets are stacked. The paper feeding cassette 3A feeds the sheets to the image forming apparatus in the right direction in FIG. 24. In FIG. 24, the sheet feeding direction from the paper feeding cassette 3A to the image forming apparatus is represented as X direction. In FIG. 24, the sheet width direction orthogonal to the sheet feeding direction (the X direction) and the up-down direction (a Z direction) is represented as Y direction. Through-holes 9A including at least passing areas in the sheet width direction of the side guides 31A and 31B are provided in the sheet tray 5A. A cushion material 53 is provided on an upstream side in the sheet feeding direction on the lower surface of the sheet tray 5A. When the paper feeding cassette 3A is present in the image forming apparatus, a downstream side in the sheet feeding direction of the sheet tray 5A is lifted upward. When the paper feeding cassette 3A is drawn out from the image forming apparatus, the sheet tray 5A drops to a bottom 45 of the paper feeding cassette 3A. The cushion material 53 eases the impact between the sheet tray 5A and the bottom 45 of the paper feeding cassette 3A when the sheet tray 5A drops.

FIG. 25 is an enlarged plan view of an edge 521A on the downstream side in the sheet feeding direction of the sheet tray 5A.

Among edges that face the through-holes 9A of the sheet tray 5A, the edge 521A on the downstream side in the sheet feeding direction extends in the sheet width direction.

FIG. 26 is a sectional view of the paper feeding cassette 3A taken along a YZ plane in a position (A) shown in FIG. 25. FIG. 27 is a sectional view of the paper feeding cassette 3A taken along an XZ plane in a position (B) shown in FIG. 25.

When the paper feeding cassette 3A is drawn out from the image forming apparatus, the sheet tray 5A drops to the bottom 45 of the paper feeding cassette 3A. If a small number of sheets are stacked on the sheet tray 5A, the cushion material 53 is held between the sheet tray 5A and the bottom 45 of the paper feeding cassette 3A. As shown in FIG. 27, the downstream side in the sheet feeding direction of the sheet tray 5A is lifted upward. Therefore, a space S having a sufficient size is formed below the through-holes 9A. When a user inserts a sheet onto the sheet tray 5A from the upstream side in the sheet feeding direction to the downstream side in the sheet feeding direction, both ends in the width direction of the sheet hang down to the space S below the through-holes 9A.

When the user moves the sheet to the downstream side in the sheet feeding direction in this state, for example, both the ends in the width direction of the sheet hung down from the sheet tray 5A enter under the edge 521A of the sheet tray 5A to be caught by the edge 521A. Therefore, setting properties of the sheet is deteriorated. If both the ends in the width direction of the hung-down sheet strongly come into contact with the edge 521A, it is likely that a bend occurs in the sheet. If the bend occurs in the sheet, it is likely that a paper jam occurs in the image forming apparatus.

If the cushion material 53 is not provided on the lower surface of the sheet tray 5A or, even if the cushion material 53 is provided, if the sheet tray 5A fells down to the bottom 45 of the paper feeding cassette 3A because a large number of sheets are stacked on the sheet tray 5A, a sheet hangs down from the upper surface of the sheet tray 5 by at least the depth of the through-holes 9A or by a space between the sheet tray 5A and the bottom 45 of the paper feeding cassette 3A. Therefore, in these cases, the sheet is caught by the edge 521A when the sheet is set and a bend occurs in the sheets. These problems tend to occur, in particular, if the sheet is easily bent or the sheet is warped in advance.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of the configuration of an image forming apparatus;

FIG. 2 is a perspective view of a paper feeding cassette;

FIG. 3 is a schematic plan view of a sheet tray in which areas of a main supporting section and sub-supporting sections are shown;

FIG. 4 is a sectional view of the sheet tray;

FIG. 5 is an enlarged sectional view of a lower surface end of the main supporting section;

FIG. 6 is a perspective view of a driving mechanism;

FIG. 7 is a sectional view of a state in which a lifting lever lifts the sheet tray upward;

FIG. 8 is a sectional view of a state in which the lifting lever releases the lifting of the sheet tray;

FIG. 9 is a sectional view of a state in which the sheet tray drops to a cassette case;

FIG. 10 is a perspective view of the sheet tray for explaining the shape of the sub-supporting sections;

FIG. 11 is an enlarged view of the sub-supporting section present on a distal end side in a cassette inserting direction;

FIG. 12 is a sectional view of the sub-supporting section taken along an XZ plane;

FIG. 13 is a plan view of the sheet tray;

FIG. 14 is a sectional view of a paper feeding cassette in a position (C) shown in FIG. 13;

FIG. 15 is a sectional view of a modification of the sub-supporting section;

FIG. 16 is a sectional view of a modification of the sub-supporting section;

FIG. 17 is a sectional view of a modification of the sub-supporting section;

FIG. 18 is a perspective view of a paper feeding cassette;

FIG. 19 is an enlarged perspective view of a sub-supporting section;

FIG. 20 is a sectional view of the paper feeding cassette taken along the XZ plane in a position (D) shown in FIG. 19;

FIG. 21 is a sectional view of a state in which a scoop-up section enters a hole;

FIG. 22 is a plan view of a width-direction scoop-up section;

FIG. 23 is diagram of the width-direction scoop-up section viewed from an arrow (E) direction shown in FIG. 22;

FIG. 24 is a perspective view of the paper feeding cassette;

FIG. 25 is an enlarged plan view of an edge on a downstream side in a sheet feeding direction of a sheet tray;

FIG. 26 is a sectional view of the paper feeding cassette taken along a YZ plane in a position (A) shown in FIG. 25; and

FIG. 27 is a sectional view of the paper feeding cassette taken along the XZ plane in a position (B) shown in FIG. 25.

DETAILED DESCRIPTION

In general, according to one embodiment, a paper feeding cassette includes a sheet storing section, side guides, and a sheet tray. The sheet storing section stores a sheet to be fed. The side guides move in the width direction orthogonal to a sheet feeding direction from the sheet storing section and regulate movement of a sheet end at least to one side in the width direction. The sheet tray lifts a downstream side end in the sheet feeding direction from the inside of the sheet storing section on the lower surface of the sheet stored in the sheet storing section. A through-hole including at least a passing area in the width direction of the side guides is provided in the sheet tray. At least a part of an edge that is present on the downstream side in the sheet feeding direction, faces the through-hole, and extends in the width direction moves closer to the sheet feeding direction as the part of the edge moves further away from the sheet center in the width direction to an end side.

First Embodiment

A first embodiment is explained below with reference to the drawings.

FIG. 1 is a diagram of the configuration of an image forming apparatus 1.

The image forming apparatus 1 is a MFP (Multi Function Peripheral). The image forming apparatus 1 includes a control section 2, a display section 11, an image reading section 12, a sheet feeding section 13, and an image forming section 14. The control section 2 includes a processor 21, a memory 22, a HDD (Hard Disk Drive) 23, and an ASIC (Application Specific Integrated Circuit) 24 and controls the entire image forming apparatus 1. The display section 11 includes an operation input section 111 configured to receive an operation input. The display section 11 displays, for example, setting of the image forming apparatus 1 and receives the operation input. The image reading section 12 is an ADF (Auto Document Feeder) and reads an original document. The sheet feeding section 13 includes plural paper feeding cassettes 3 configured to store sheets, pickup rollers 131 configured to pick up the sheets from the paper feeding cassettes 3 one by one, sheet sensors 132 configured to detect presence or absence of the sheets in the paper feeding cassettes 3, a conveying path 133 for conveying the sheets to the image forming section 14, and paper feeding rollers 134 configured to feed the sheets picked up by the pickup rollers 131 to the conveying path 133. The image forming section 14 includes a transfer belt 141 configured to transfer a toner image onto the sheet conveyed from the sheet feeding section 13 and a fixing device 142 configured to heat and press the sheet and fix the toner image on the sheet.

FIG. 2 is a perspective view of the paper feeding cassette 3. In FIG. 2, the upward direction is represented as Z direction, a sheet feeding direction from the paper feeding cassette 3 to the image forming apparatus 1, which is a direction orthogonal to the Z direction, is represented as X direction, and the width direction of sheets stacked on the paper feeding cassette 3, which is a direction orthogonal to the X and Z directions, is represented as Y direction.

The paper feeding cassette 3 includes a cassette case 4 (a sheet storing section), side guides 31A, 31B, 32A, and 32B, an end guide 33, a sheet tray 5 (a tray), and a tray driving mechanism 6 (FIG. 6).

The cassette case 4 stores sheets to be fed to the image forming apparatus 1. The cassette case 4 includes walls 41 to 44 and a bottom 45. Ends of the walls 41 to 44 are connected to one another vertically. Among the walls 41 to 44, the wall 41 provided near the pickup roller 131 (FIG. 1) extends in the sheet width direction and regulates movement of the sheets in a downstream side in the sheet feeding direction. The sheets are stored in a space surrounded by the wall 41, the side guides 31A, 31B, 32A, and 32B, the end guide 33, and the sheet tray 5. The bottom 45 is connected to the lower ends of the walls 41 to 44 and closes an opening surrounded by the walls 41 to 44.

The side guides 31A, 31B, 32A, and 32B extend in the sheet feeding direction. The side guides 31A and 31B are opposed to each other in the sheet width direction across the sheet tray 5. The side guides 32A and 32B are provided further on an upstream side in the sheet feeding direction than the side guides 31A and 31B and opposed to each other in the sheet width direction not across the sheet tray 5. The side guides 31A, 31B, 32A, and 32B slide in the sheet width direction. The bottoms of the side guides 31A and 32A on the inner side in FIG. 2 are connected to each other via a tabular member. The bottoms of the side guides 31B and 32B on the front side in FIG. 2 are also connected to each other via a tabular member. When the side guides 31A and 31B on one side are moved to the center side in the sheet width direction of the cassette case 4, the side guides 31A and 31B on the other side also move to the center side in the sheet width direction of the cassette case 4. A user moves the side guides 31A, 31B, 32A, and 32B to the center side in the sheet width direction of the cassette case 4 according to a sheet size to regulate the movement of the sheets in the sheet width direction using the side guides 31A, 31B, 32A, and 32B.

The end guide 33 is provided in the center in the sheet width direction of the cassette case 4 and opposed to the wall 41 across the sheet tray 5. The end guide 33 slides in the sheet feeding direction. In FIG. 2, the end guide 33 and the side guides 31A and 31B are present in positions for regulating, in cooperation with the wall 41, movement of A4-size sheets in the sheet feeding direction and the sheet width direction.

The sheet tray 5 lifts the downstream side end in the sheet feeding direction on the lower surface of the sheets and causes the pickup roller 131 to pick up a sheet. Through-holes 9 including at least passing areas in the sheet width direction of the side guides 31A and 31B are provided in the sheet tray 5. The sheet tray 5 includes a main supporting section 51 and sub-supporting sections 52.

The main supporting section 51 is provided on the center side in the sheet width direction of the cassette case 4 and extends in the sheet feeding direction. The main supporting section 51 supports the lower surface of the sheets and turns up and down around the upstream side in the sheet feeding direction.

FIG. 3 is a plan view of the sheet tray 5 in which areas of the main supporting section 51 and the sub-supporting sections 52 are shown.

The main supporting section 51 is provided between the through-holes 9, i.e., on the center side in the sheet width direction of the cassette case 4. The main supporting section 51 includes a main body section 511 that extends in the sheet feeding direction, a bridging section 512 that extends from the upstream side in the sheet feeding direction of the main body section 511 to both sides in the sheet width direction, side sections 513 that extend from sides near the walls 42 and 44 of the bridging section 512 to both sides in the sheet feeding direction along the walls 42 and 44, and standing sections 514 (see FIG. 2) that stand from the walls 42 and 44 sides of the side sections 513 along the walls 42 and 44.

The sub-supporting sections 52 extend from the downstream side in the sheet feeding direction of the main supporting section 51 to both the sides in the sheet width direction and are connected to the downstream end in the sheet feeding direction of the side section 513. The sub-supporting sections 52 extend over the passing areas of the side guides 31A and 31B and support the downstream side in the sheet feeding direction of the sheets.

FIG. 4 is a sectional view of the sheet tray 5.

A cutout section 515 is provided on the upstream side in the sheet feeding direction of the standing section 514. A rotation fulcrum 46 that projects from the walls 42 and 44 opposed to the standing section 514 is inserted through the cutout section 515. The sheet tray 5 turns up and down around the rotation fulcrum 46. On the lower surface of the main supporting section 51, an upstream side end 516 in the sheet feeding direction approaches and separates from the bottom 45 of the cassette case 4 according to the turning of the main supporting section 51. As shown in FIG. 5 in enlargement, a cushion material 53 is fixed to the upstream side end 516 of the main supporting section 51.

FIG. 6 is a perspective view of the tray driving mechanism 6.

The tray driving mechanism 6 lifts the downstream side in the sheet feeding direction of the sheet tray 5 upward when the paper feeding cassette 3 is present in the image forming apparatus 1. The tray driving mechanism 6 includes a lifting lever 61, a drive coupling shaft 62, and a lever driving section 63. The lifting lever 61 lifts the downstream side in the sheet feeding direction of the sheet tray 5 upward. The drive coupling shaft 62 is connected to the lower end of the lifting lever 61 and extends, in the sheet width direction, to the distal end side in an inserting direction of the paper feeding cassette 3 into the image forming apparatus 1. In the drive coupling shaft 62, a coupling 621 is provided on the distal end side in the cassette inserting direction. The lever driving section 63 includes a driving coupling 631 coupled to the coupling 621. The lever driving section 63 turns the lifting lever 61 via the drive coupling shaft 62.

When the paper feeding cassette 3 is present in the image forming apparatus 1, the lever driving section 63 turns the lifting lever 61 upward via the drive coupling shaft 62 and, as shown in FIG. 7, lifts the downstream side in the sheet feeding direction of the sheet tray 5 upward. When the paper feeding cassette 3 is drawn out from the image forming apparatus 1, the couplings 621 and 631 are uncoupled. As shown in FIGS. 8 and 9, the downstream side in the sheet feeding direction of the sheet tray 5 drops. At that point, the cushion material 53 enters between the sheet tray 5 and the bottom 45 of the cassette case 4, eases the impact of the drop of the downstream side in the sheet feeding direction of the sheet tray 5, and prevent the sheet tray 5 from forcefully colliding against the bottom 45 of the cassette case 4 to cause large sound.

If a small number of sheets are placed on the sheet tray 5, when the paper feeding cassette 3 is drawn out from the image forming apparatus 1, the cushion material 53 enters between the sheet tray 5 and the bottom 45 of the cassette case 4, whereby the downstream side in the sheet feeding direction of the sheet tray 5 is lifted.

FIG. 10 is a perspective view of the sheet tray 5 for showing edges 521.

The sub-supporting sections 52 on the downstream side in the sheet feeding direction of the sheet tray 5 include the edges 521 that face the through-holes 9 and extend in the sheet width direction.

FIG. 11 is an enlarged view of the sub-supporting section 52 provided on the distal end side in the cassette inserting direction.

In the sub-supporting section 52 provided on the distal end side in the cassette inserting direction, an opening for sensor 522 is provided between the edge 521 and the wall 41. If there is no sheet on the sheet tray 5, light emitted from the sheet sensor 132 provided above the sheet tray 5 passes through the opening for sensor 522 and, after reflecting on the bottom 45 of the cassette case 4, passes through the opening for sensor 522 again and is received by the sheet sensor 132. The sheet sensor 132 detects presence or absence of sheets according to whether the emitted light is blocked by the sheets. Alternatively, the sheet sensor 132 detects whether the number of remaining sheets is equal to or smaller than a fixed number according to whether the emitted light is blocked by an actuator configured to operate if the number of sheets is equal to or smaller than the fixed number.

The sub-supporting section 52 includes a sub-supporting section main body 523 (a supporting section main body) configured to support sheets and a sheet guide section 524 that extends downward from the upstream side in the sheet feeding direction of the sub-supporting section main body 523. The edge 521 of the sub-supporting section 52 is the edge 521 of the sheet guide section 524. At least a part of the edge 521 tilts to move closer to the sheet feeding direction as the part of the edge 521 moves further away from the sheet center to an end side in the width direction. A section corresponding to the sheet center side in the sheet width direction in the edge 521 is provided further on the upstream side in the sheet feeding direction than the opening for sensor 522. A section corresponding to the sheet end side in the sheet width direction in the edge 521 is provided on the sheet width direction from the opening for sensor 522. The edge 521 of the sub-supporting section 52 on the proximal end side in the cassette inserting direction tilts to move closer to the sheet feeding direction as the edge 521 moves further away from the sheet center to the end side in the sheet width direction (FIG. 10).

As shown in FIG. 11, the sheet guide section 524 is also provided at a corner 54 of the main supporting section 51 and the sub-supporting section 52. The sheet guide section 524 at the corner 54 curves in an arcuate shape in plan view. The main supporting section 51 includes a sheet guide section 517 that curves downward from the main body section of the main supporting section 51. The sheet guide section 517 is connected to the sheet guide section 524 of the sub-supporting section 52 at the corner 54. An edge 518 of the main supporting section 51 is the edge 518 of the sheet guide section 517.

FIG. 12 is a sectional view of the sub-supporting section 52 taken along an XZ plane.

The sheet guide section 524 curves downward from the sub-supporting section 52. A lower end face 525 of the sheet guide section 524 faces down and is parallel to the sub-supporting section main body 523. The sheet guide section 524 is formed by, for example, bending and drawing the sheet tray 5. The sheet guide section 517 of the main supporting section 51 has structure same as that of the sheet guide section 524 of the sub-supporting section 52.

FIG. 13 is a plan view of the sheet tray 5.

At least a part of the edge 521 of the sheet tray 5 tilts to move closer to the sheet feeding direction as the part of the edge 521 moves further away from the sheet center to the end side in the sheet width direction. The action performed by the edge 521 when the user places the downstream side in the sheet feeding direction of a sheet on the sheet tray 5 and moves the sheet to the downstream side in the sheet feeding direction in a state in which both ends in the sheet width direction hang further downward than the sheet tray 5 is explained below.

When the sheet is present in a position (i) on the upstream side in the sheet feeding direction on the main supporting section 51 of the sheet tray 5, the sheet hangs further downward as the sheet moves further away in the sheet width direction from the edge 518 of the main supporting section 51.

When the sheet is moved to the downstream side in the sheet feeding direction by the user and, as indicated by (ii), comes into contact with the edge 521 of the corner 54, a part of the downstream side in the sheet feeding direction of the sheet is scooped up onto the sub-supporting section 52 along the arcuate edge 521 of the corner 54.

FIG. 14 is a sectional view of the paper feeding cassette 3 taken along the XZ plane in a position (C) shown in FIG. 13.

When the sheet further moves to the downstream side in the sheet feeding direction from the position of (ii), the edge 521 tilts to move closer to the sheet feeding direction as the edge 521 moves further away from the sheet center to the end side in the sheet width direction. As shown in FIG. 14 and indicated by (iii) and (iv) shown in FIG. 13, according to the movement of the sheet to the downstream side in the sheet feeding direction, the sheet is gradually scooped up by the edge 521 and moves onto the sub-supporting section 52. When the sheet moves to a position in contact with the wall 41, the downstream side end in the sheet feeding direction of the sheet entirely moves onto the main supporting section 51.

As explained above, in this embodiment, when the sheet is inserted onto the sheet tray 5 and the sheet is moved to the downstream side in the sheet feeding direction, the hung-down portions of the sheet can be gradually scooped up onto the sub-supporting section 52 by the edge 521. Therefore, in this embodiment, setting properties of the sheet in the paper feeding cassette 3 can be improved. In this embodiment, since the sheet is gradually scooped up, it is possible to prevent the sheet from strongly coming into contact with the sub-supporting section 52. Therefore, it is possible to prevent a bend of the sheet and suppress a sheet jam caused by the bent sheet conveyed into the image forming apparatus 1.

The lower end face 525 of the sheet guide section 524 faces down and is parallel to the sub-supporting section main body 523. Therefore, it is possible to satisfactorily prevent the sheet from entering the lower side of the sheet guide section 524 compared with a case where the lower end face 525 faces the outer side of the sub-supporting section 52. Since the sheet guide section 524 curves downward from the sub-supporting section main body 523, it is possible to more satisfactorily prevent the sheet from entering the lower side of the sheet guide section 524.

As shown in FIG. 15, a sheet guide section 524B may tilt downward from the sub-supporting section main body 523. In sectional view of the sheet guide section 524B viewed from the sheet width direction, an angle formed by the sub-supporting section main body 523 and the sheet guide section 524B may be 145°.

As shown in FIG. 16, a sheet guide section 524C may extend downward vertically from the sub-supporting section main body 523.

As shown in FIG. 17, a sub-supporting section 52D may be formed in a flat plate shape. An edge 521D may be an end face 526 of the sub-supporting section 52D that faces a side.

The sheet tray 5 may include only the sub-supporting section 52 on one side.

Second Embodiment

A paper feeding cassette according to a second embodiment is explained below. Sections having the same functions as those in the first embodiment are denoted by the same reference numerals and signs and explanation of the sections is omitted.

FIG. 18 is a perspective view of a paper feeding cassette 3E.

The paper feeding cassette 3E includes a cassette case 4E, the side guides 31A, 31B, 32A, and 32B, the end guide 33, a sheet tray 5E, and the tray driving mechanism. Among these components, the side guides 31A, 31B, 32A, and 32B, the end guide 33, and the tray driving mechanism are the same as those in the first embodiment.

As in the first embodiment, the edge 521 of the sub-supporting section 52 provided on one end side in the sheet width direction (the proximal end side in the cassette inserting direction) tilts to move closer to the sheet feeding direction as the edge 521 moves further away from the sheet center to the end side in the sheet width direction. The edge 521 scoops up one end side in the sheet width direction of a sheet onto the sub-supporting section 52.

FIG. 19 is an enlarged perspective view of a sub-supporting section 52E on the other end side in the sheet width direction (the distal end side in the cassette inserting direction).

On a bottom 45E of the cassette case 4E, a projecting section 47 is provided further on the upstream side in the sheet feeding direction than the sub-supporting section 52E. The projecting section 47 extends in the sheet width direction over passing areas of the side guides 31A and 31B. The projecting section 47 includes a slope 471 that faces the upstream side in the sheet feeding direction.

In the sub-supporting section 52E, a cutout section 527 recessed to the downstream side in the sheet feeding direction is provided on the upstream side in the sheet feeding direction. Light emitted from the sheet sensor 133 (FIG. 1) is made incident on the bottom 45E of the cassette case 4E through a space S1 surrounded by the cutout section 527.

The sheet tray 5E includes an elastic sheet 7 fixed on the sub-supporting section 52E by, for example, bonding by an adhesive. Unlike the sub-supporting section 52 on one end side in the sheet width direction, the sub-supporting section 52E on the other end side in the sheet width direction scoops up the other end side in the sheet width direction of a sheet onto the sub-supporting section 52E using the elastic sheet 7 and the slope 471. In the projecting section 47, a section corresponding to the cutout section 527 in the sheet width direction is higher in the Z direction than a section corresponding to the elastic sheet 7 in the sheet width direction.

The elastic sheet 7 includes an elastic sheet main body section 71 fixed on the sub-supporting section 52E and a scoop-up section 72 that is bent downward from the elastic sheet main body section 71 and extends downward from the sub-supporting section 52E. The scoop-up section 72 extends from the passing area of the side guide 31A to the cutout section 527 in the sheet width direction. The scoop-up section 72 includes a sheet-feeding-direction scoop-up section 721 and a width-direction scoop-up section 722.

The width-direction scoop-up section 722 is formed by bending, in the sheet feeding direction, an end of the sheet-feeding-direction scoop-up section 721 that extends in the sheet width direction. The width-direction scoop-up section 722 tilts with respect to the sheet feeding direction and enters the inside of the space S1 surrounded by the cutout section 527.

FIG. 20 is a sectional view of the paper feeding cassette 3E taken along the XZ plane in a position (D) shown in FIG. 19. The sub-supporting section 52E and the sheet-feeding-direction scoop-up section 721 are shown in the figure.

The sub-supporting section 52E includes a tongue section 528 that is bent downward from the sub-supporting section main body 523 configured to support a sheet on the sub-supporting section 52E. The tongue section 528 is formed by, for example, bending and drawing the sheet tray 5.

The sheet-feeding-direction scoop-up section 721 is formed by bending the elastic sheet main body section 71 downward. A base portion of the sheet-feeding-direction scoop-up section 721 is fixed on the tongue section 528 by bonding. This makes it possible to stabilize an angle of the sheet-feeding-direction scoop-up section 721 at an angle same as an angle of the tongue section 528.

In this embodiment, as in the first embodiment, for example, if the number of sheets on the sheet tray 5E is small, a cushion material is held between the bottom 45E of the cassette case 4E and the sheet tray 5E, whereby the downstream side in the sheet feeding direction of the sheet tray 5E is lifted upward. At this point, the top end of the slope 471 is present in a position higher than the bottom end of the sheet-feeding-direction scoop-up section 721.

When a sheet is moved to the downstream side in the sheet feeding direction by a user, as indicated by (i), first, the other end side in the sheet width direction of the sheet hung down from the sheet tray 5E comes into contact with the slope 471 and is lifted upward by the slope 471.

When the sheet is moved to the downstream side in the sheet feeding direction by the user, as indicated by (ii), the other end side in the sheet width direction of the sheet is lifted further upward by the sheet-feeding-direction scoop-up section 721. The other end side in the sheet width direction of the sheet is finally scooped up onto the sub-supporting section 52E by the sheet-feeding-direction scoop-up section 721 according to the movement of the sheet to the downstream side in the sheet feeding direction and supported by the sub-supporting section 52E.

On the bottom 45E of the cassette case 4E, a hole 48 is provided between the projecting section 47 and a section under the sub-supporting section 52E. As shown in FIG. 19, the hole 48 includes a first hole 481 that extends in the sheet width direction in plan view and a second hole 482 that is bent to the sheet feeding direction side in plan view. As shown in FIG. 21, when the sheet tray 5E falls down to the bottom 45E, the sheet-feeding-direction scoop-up section 721 enters the first hole 481 that extends in the sheet width direction. The width-direction scoop-up section 722 enters the second hole 482 that is bent to the sheet feeding direction side.

As shown in FIG. 21, the hole 48 pierces through the bottom 45E. An elastic sheet regulating surface 483 is provided on the wall surface on the downstream side in the sheet feeding direction of the hole 48. The elastic sheet regulating surface 483 tilts with respect to the sheet feeding direction and faces the upstream side in the sheet feeding direction. When the scoop-up section 72 enters the hole 48, the elastic sheet regulating surface 483 regulates a projecting direction of the scoop-up section 72 on the rear surface side of the bottom 45E to a direction in which the scoop-up section 72 avoids a structure 81 provided on the rear surface side of the bottom 45E. In this embodiment, the elastic sheet regulating surface 483 bends the scoop-up section 72 to the upstream side in the sheet feeding direction. The elastic sheet regulating surface 483 guides the projecting direction of the scoop-up section 72 on the rear surface side of the bottom 45E to the upstream side in the sheet feeding direction. The elastic sheet regulating surface 483 regulates a projection amount of the scoop-up section 72 on the rear surface side of the bottom 45E to an amount equal to or smaller than a predetermined amount.

FIG. 22 is a plan view of the width-direction scoop-up section 722. FIG. 23 is a diagram of the width-direction scoop-up section 722 viewed from an arrow (E) direction shown in FIG. 22.

When a sheet is inserted onto the sheet tray 5E in the sheet width direction, the width-direction scoop-up section 722 lifts upwards the downstream side end in the sheet feeding direction of the sheet hung down to the inside of the space S1 surrounded by the cutout section 527 and prevents the sheet from being caught by the cutout section 527.

According to the second embodiment, it is possible to provide, for example, techniques (1) to (5) explained below.

(1) A paper feeding cassette including:

a sheet storing section configured to store a sheet to be fed, the sheet storing section including a projecting section that projects from the bottom of the sheet storing section and extends in the width direction of the sheet and has a slope that faces an upstream side in a sheet feeding direction from the inside of the sheet storing section;

side guides that are provided further on the upstream side in the sheet feeding direction than the projecting section and extend in the width direction, slide in the width direction, and regulate movement of the sheet at least to one side of the width direction; and

a sheet tray in which a through-hole including at least a passing area in the width direction of the side guide is provided, the sheet tray including a supporting section that lifts a downstream side end in the sheet feeding direction on the lower surface of the sheet stored in the sheet storing section and an elastic sheet including a scoop-up section that extends downward from the supporting section and fixed to the supporting section.

(2) The paper feeding cassette of (1), wherein

a cushion material is fixed on the upstream side in the sheet feeding direction on the lower surface of the sheet tray and, when there is no sheet on the sheet tray, the cushion material is held between the bottom and the sheet tray, whereby the downstream side in the sheet feeding direction of the sheet tray is lifted upward, and

the top end of the slope is present in a position higher than the bottom end of the scoop-up section.

(3) The paper feeding cassette of (1), wherein the hole where the scoop-up section enters when the sheet tray falls down to the bottom is provided between the projecting section and a section under the supporting section on the bottom. (4) The paper feeding cassette of (3), wherein the hole pierces through the bottom and includes an elastic sheet regulating surface configured to regulate a projecting direction of the scoop-up section on the rear surface side of the bottom. (5) The paper feeding cassette of (1), further including:

a rotation fulcrum configured to rotate the sheet tray around the upstream side in the sheet feeding direction of the sheet tray;

a tray driving mechanism configured to lift the downstream side in the sheet feeding direction of the sheet tray upward; and

a cushion material fixed near the rotation fulcrum on the lower surface of the sheet tray and configured to ease the impact of collegian of the sheet tray and the bottom when the tray driving mechanism releases lifting of the sheet tray and the sheet tray drops to the bottom.

As explained above in detail, according to the technique described in this specification, it is possible to provide a technique for stacking sheets using a paper feeding cassette.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of invention. Indeed, the novel apparatus, methods and system described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the apparatus, methods and system described herein may be made without departing from the sprit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. 

1. A paper feeding cassette comprising: a sheet storing section configured to store a sheet to be fed; side guides configured to move in a width direction orthogonal to a sheet feeding direction from the sheet storing section and regulate movement of a sheet end at least to one side in the width direction; and a sheet tray configured to lift a downstream side end in the sheet feeding direction from an inside of the sheet storing section on a lower surface of the sheet stored in the sheet storing section, a through-hole including at least a passing area in the width direction of the side guides being provided in the sheet tray and at least a part of an edge that is present on the downstream side in the sheet feeding direction, faces the through-hole, and extends in the width direction moving closer to the sheet feeding direction as the part of the edge moves further away from a sheet center in the width direction to an end side.
 2. The paper feeding cassette according to claim 1, wherein the sheet tray includes a supporting section main body configured to support the sheet and a sheet guide section that extends downward from the supporting section main body, and the edge is an edge of the sheet guide section.
 3. The paper feeding cassette according to claim 2, wherein a lower end face of the sheet guide section faces down and is parallel to the supporting section main body.
 4. The paper feeding cassette according to claim 3, wherein the sheet guide section tilts downward from the supporting section main body, and an angle formed by the supporting section main body and the sheet guide section is 145° in sectional view of the sheet guide section taken along in the sheet feeding direction.
 5. The paper feeding cassette according to claim 3, wherein the sheet guide section curves downward from the supporting section main body.
 6. The paper feeding cassette according to claim 3, wherein the sheet guide section extends downward vertically from the supporting section main body.
 7. The paper feeding cassette according to claim 1, wherein the sheet tray has a flat plate shape, and the edge in contact with the through-hole is an end face of the sheet tray that faces a side.
 8. The paper feeding cassette according to claim 1, further comprising a sheet sensor configured to emit light to the downstream side in the sheet feeding direction on the sheet on the sheet tray and receive reflected light, wherein an opening for sensor through which the light emitted from the sheet sensor passes is provided on the downstream side in the sheet feeding direction of the edge in the sheet tray.
 9. The paper feeding cassette according to claim 8, wherein a section of the edge corresponding to the sheet center side in the width direction is present further on the upstream side in the sheet feeding direction than the opening for sensor, and a section of the edge corresponding to the sheet end side in the width direction is present on the width direction from the opening for sensor.
 10. The paper feeding cassette according to claim 1, wherein at least a pair of the side guides are provided and the side guides are opposed to each other in the width direction and regulate movement of sheet both ends in the width direction.
 11. The paper feeding cassette according to claim 1, wherein a cushion material is provided on at least one of the upstream side in the sheet feeding direction on a lower surface of the sheet tray and a bottom of the paper feeding cassette opposed to the upstream side in the sheet feeding direction on the lower surface of the sheet tray.
 12. The paper feeding cassette according to claim 1, wherein the paper feeding cassette is drawn out in the width direction from an apparatus that houses the paper feeding cassette.
 13. An image forming apparatus comprising: a sheet storing section configured to store a sheet to be fed; side guides configured to move in a width direction orthogonal to a sheet feeding direction of the sheet stored in the sheet storing section from an inside of the sheet storing section and regulate movement of a sheet end at least to one side in the width direction; and a sheet tray configured to lift a downstream side end in the sheet feeding direction from the inside of the sheet storing section on a lower surface of the sheet stored in the sheet storing section, a through-hole being formed in an area including at least a passing area in the width direction of the side guides and at least a part of an edge that is present on the downstream side in the sheet feeding direction of the through-hole and extends in the width direction moving closer to the sheet feeding direction as the part of the edge moves further away from a sheet center in the width direction to an end side.
 14. The apparatus according to claim 13, wherein the sheet tray includes a supporting section main body configured to support the sheet and a sheet guide section that extends downward from the supporting section main body, and the edge is an edge of the sheet guide section.
 15. The apparatus according to claim 14, wherein a lower end face of the sheet guide section faces down and is parallel to the supporting section main body.
 16. The apparatus according to claim 15, wherein the sheet guide section tilts downward from the supporting section main body, and an angle formed by the supporting section main body and the sheet guide section is 145° in sectional view of the sheet guide section taken along in the sheet feeding direction.
 17. The apparatus according to claim 15, wherein the sheet guide section curves downward from the supporting section main body.
 18. The apparatus according to claim 15, wherein the sheet guide section extends downward vertically from the supporting section main body.
 19. The apparatus according to claim 15, wherein the sheet tray has a flat plate shape, and the edge in contact with the through-hole is an end face of the sheet tray that faces a side.
 20. The apparatus according to claim 13, further comprising a sheet sensor configured to emit light to the downstream side in the sheet feeding direction on the sheet on the sheet tray and receive reflected light, wherein an opening for sensor through which the light emitted from the sheet sensor passes is provided on the downstream side in the sheet feeding direction of the edge in the sheet tray. 